1. Field of the Invention
The present invention relates to temperature control systems and methods and more particularly, but not by way of limitation, to critical care thermal therapy systems utilizing a temperature control module operated in conjunction with a remotely disposed monitoring system enhancing performance and reliability of the thermal control over a patient's body in a manner particularly suited for neonatal care and other critical care.
2. History of the Prior Art
Medical care providers have long recognized the need to provide warmth and/or cooling directly to patients as part of routine treatment and therapy. For example, faster and more efficient recoveries have been reported using cold therapy for orthopedic patients. Moreover, the benefits of warming patients undergoing surgery has been conclusively proven.
Several methods, devices, and systems have been developed that deliver temperature controlled fluids through pads or thermal blankets to achieve the above purpose. Typically these devices and systems have heating and/or cooling elements, a source for the temperature controlled fluid, a pump for forcing the temperature controlled fluid through the pad, blanket, or other patient cover and a thermal interface between the patient and the temperature controlled fluid. U.S. Pat. No. 4,884,304 to Elkins is directed to a mattress-cover device which contains liquid flow channels which provide the selective heating or cooling by conduction.
Cooling blankets have also been proposed such as the blanket disclosed in U.S. Pat. No. 4,660,388 to Greene. Greene discloses a cooling cover having an inflatable pad with plenum chambers at opposite ends thereof. Cool air is generated in a separate unit and directed to the pad and out a number of apertures on the underside of the pad and against the body of the person using the cover.
A disposable heating or cooling blanket is disclosed in U.S. Pat. No. 5,125,238 to Ragan, et al. which has three layers of flexible sheeting. Two of the layers form an air chamber and the third includes a comfortable layer for contact with the patient. Conditioned air is directed toward the covered person through a multiplicity of orifices in the bottom layers of the blanket. Another system is set forth and shown in U.S. Pat. No. 5,989,285, assigned to the assignee of the present invention.
More recently the advantages of thermal control have been realized for critical care patients such as neonatal babies and stroke victims. Accurate critical care with thermal therapy systems require not only a temperature controlled fluid, but also the monitoring of the body temperature of the patient. It is critical that a reliable thermal response is used to achieve the desired core body temperature. Several problems are inherent, however, in prior art systems which lack fast and accurate temperature control in response to monitored temperature values. Time delays can result in thermal overshoot by the system, reducing patient effectiveness.
The key issue in accurate temperature control is indeed providing a system which incorporates a monitoring system having real-time temperature reading and a system response in proportion to the thermal measurements taken for the patient being treated. In other words, a sensed temperature of the patient's body evokes a thermal response which is directly associated therewith and without a time delay therefrom. Time delays between the detection of a denied thermal deviation and the delivery of the necessary heat or cold can, as referenced above, be deleterious. A system which provides the delivery of the necessary heat or cold within a short response period is necessary for true critical care through thermal therapy. It is therefore important that modem thermal therapy systems reduce the time differential substantially in order to afford the delivery of the necessary heat or cold to the patient's body for the requisite therapeutic effect.
It should be further noted that thermal therapy in critical care situations may be required in mobile intensive care units. Strokes often occur away from hospitals and comprise the genesis of basic lifesaving scenarios of the type where thermal therapy may be a critical life, or quality of life, saving factor. If an effective critical care thermal therapy system is not provided in a mobile configuration operable with multiple forms of power (such as AC and/or DC current) the utilization of the system is limited. The availability of a critical care system should not be dependent upon a single form of power.
The present invention addresses these considerations and affords an improvement over the prior art by providing an efficient thermal therapy system with real-time feedback monitored thermal response to uniformly heat or cool fluid delivered to a patient when and where the patient is in need. The present invention further includes a system that is operable on both AC and/or DC current and in an optionally portable configuration to facilitate use within automobile, care flight and other mobile configurations.